Because you did not think logically or thinking a real-world scenario

The cost of an item or the revenue is always the quantity \(\times\) the price

I would say: sell 10 TV $1000 each I gain $10,000. Pretty straight

Now, the profit is = revenue - costs, and the difference I charge over the sell is the mark-up

If x is the quantity

C is the price to buy them

R is the price I made selling them.

Of course, my profit what I gain is the quantity x \(\times\) the selling price minus the buy price

I buy 10 apples one dollar each I spend 10 dollars

I sell 10 apples for 1.5 dollars so my gain is 15

My revenue is 10 apples at 15 dollars in total with my profit of 5 dollars.

\(x(r-c)\)

Why did you used algebra ?? makes no sense


I hope this helps